Changes
Catalog no. LF-97-1801
ISBN 0-89278-981-6
Subject: Changes in the state of substances
Students expand their understanding of solids, liquids, and gases by exploring changes in state. They investigate freezing, melting, evaporation, and condensation of water. In a sequence of lessons, students produce a mixture of two solids and a mixture of solids with liquids and observe the results. They work through several methods to separate mixtures: sieving, filtration, evaporation, and chromatography. The students set up races that involve sugar dissolving in water and observe the effects of particle size and water temperature on the rate at which the sugar dissolves. They also observe crystals formed as a result of evaporation. Students observe some changes that occur immediately and some that occur over time, and they begin to recognize the characteristics of chemical reactions. They investigate rusting, and they observe and collect the gas formed by mixing an effervescent tablet in water. Students have several opportunities to practice their new skills in lessons in which they devise ways of separating a mystery mixture and plan and carry out investigations that involve other changes.

Comparing and Measuring
Catalog no. LF-97-1301
ISBN 0-89278-990-5
Subject: Concepts of measurement
Students explore the concepts that underlie the science skills of comparing and measuring. The lessons are based on a developmental sequence that includes three activities: comparing, matching, and measuring. Initially, students compare lengths by matching measuring tape to their own heights and the lengths of their arms and legs. They make the transition from matching to measuring length by quantifying nonstandard units of measure (in this case, their own feet) and discover that using nonstandard units of measure produces varied results. Finally, students use standard units of measure, such as Unifix® cubes and measuring strips, to measure height, width, and distance. In so doing, students begin to understand key measuring concepts, such as using beginning and ending points, a common starting line, and standard units of measure.

Ecosystems
Catalog no. LF-97-2801
ISBN 0-89278-948-4
Subject: Environmental interrelationships
Students begin the unit by setting up a terrarium in which they grow grass, mustard, and alfalfa plants. They then add crickets and isopods. They also set up an aquarium into which they introduce snails, guppies, elodea, algae, and duckweed. By connecting the terrarium and aquarium bottles to create an “ecocolumn,” students are able to observe the relationship between the two environments and the organisms living within them. Using test ecocolumns that contain only plants, students simulate the effects of pollutants—such as road salt, fertilizer, and acid rain—on an environment. Students then use a food chain wheel to make inferences about the effects these pollutants might have on their own miniature ecosystems. Later, students read about, explore, and discuss the Chesapeake Bay as a model ecosystem. They analyze this ecosystem from the viewpoint of various users—waterman, dairy farmer, land developer, recreational boater, and resident—and present their findings to the class. This activity enables students to appreciate the trade-offs that must be made to reach mutually acceptable solutions to environmental problems.

Food Chemistry
Catalog no. LF-97-2901
ISBN 0-89278-945-X
Subject: Basic food and nutrition concepts
Students explore basic concepts related to food and nutrition. They set up their own classroom laboratory and perform physical and chemical tests to identify the presence of starch, glucose, fats, and proteins in common foods. Some of the tests are relatively simple and produce “yes-or-no” results; others require multiple steps. Still other tests, such as the glucose test, produce results that require interpretation. Through readings, students discover how proteins, fats, and carbohydrates, as well as vitamins, are related to good health. They also learn how to interpret food labels. In a final challenge, students apply their knowledge and skills to analyze the nutritional components of a marshmallow.

The Life Cycle of Butterflies
Catalog no. LF-97-1501
ISBN 0-89278-987-5
Subject: Animal life cycles
This unit introduces students to the concept of life cycles by inviting them to investigate one organism—the painted lady butterfly (Vanessa cardui). During an eight-week period, students observe, record, and describe the metamorphosis from caterpillar to chrysalis and from chrysalis to butterfly. In many cases, they watch the butterfly lay eggs. The butterfly ultimately dies a natural death, thereby completing students’ observations of the life cycle. The children compare the life cycle of the butterfly with that of other organisms, an experience that deepens their understanding of the diversity of life and the patterns that characterize animal life cycles.

Motion and Design
Catalog no. LF-97-3001
ISBN 0-89278-954-9
Subject: Properties and characteristics of motion
Students explore the physics of motion and to apply these concepts to technological design. Using plastic construction materials, weights, rubber bands, and propellers, students design and build vehicles. Students record their designs using technical two-view and three-view drawings. They test how fast the vehicles move and use their findings to redesign the vehicles to move more efficiently. Cost analysis is one of the students’ design requirements. As students design their vehicles, they intuitively apply concepts such as friction and kinetic and potential energy. They also explore the effect of gravity on motion. The unit concludes by challenging students to solve a design challenge and to present their findings to the class.

Organisms
Catalog no. LF-97-1101
ISBN 0-89278-999-9
Subject: Basic characteristics of living things
This unit helps students develop an understanding of and sensitivity to living things. Students create and maintain a woodland habitat containing pine seedlings, moss, pill bugs, and Bess beetles or millipedes. They also set up and observe a freshwater habitat into which they introduce elodea and cabomba plants, pond snails, and guppies. With both plants and animals in each habitat, students have the opportunity to observe how these organisms coexist. Through studying the needs and characteristics of a variety of organisms, the students are able to draw conclusions about how plants and animals are similar and different. In a final lesson, students apply to humans what they have learned about organisms, exploring how human beings are similar to and different from other living things.

Plant Growth and Development
Catalog no. LF-97-1901
ISBN 0-89278-975-1
Subject: Plant life cycle
Students observe each stage in the life cycle of a simple plant. Working with Wisconsin Fast Plants® (Brassica rapa), which germinate, mature, and go to seed within a 40-day period, students plant seeds and watch the seedlings emerge. Later, they thin and transplant seedlings. As they watch their plants grow, students learn that plants need nutrients from the soil, as well as water and light, to thrive. As the unit expands to focus on the interdependence of living things, students cross-pollinate the flowers with dried honeybees. Finally, they harvest mature seeds and determine seed yields. These experiences deepen students’ understanding of the characteristics of living organisms and their relationship with and dependence on their environment.

Rocks and Minerals
Catalog no. LF-97-2001
ISBN 0-89278-972-7
Subject: Rocks and minerals
Students explore the differences and similarities between rocks and minerals by investigating samples of these earth materials, performing a series of tests similar to geologists’ field tests, and reading about rocks and minerals and how they are used. The first lessons focus on rocks. The students then turn their attention to a set of 12 minerals and test them to identify properties such as streak color, luster, transparency, hardness, shape, and magnetism. After completing these observations, students compile them into their own “Minerals Field Guide.” In a culminating activity, they are challenged to apply their knowledge and skills to identify new minerals. They then report on how rocks and minerals are used.

Soils
Catalog no. LF-97-1601
ISBN 0-89278-984-0
Subject: Components and properties of soil
Students investigate the chief components of soil—sand, clay, and humus—and explore the relationship between soil and plant growth. Early in the unit, they create their own compost bags. This activity enables them to observe the decomposition of organic materials over time. Students observe and read about earthworms to learn about their connection to plant roots and soil. The students also conduct tests that enable them to observe and compare such properties of soil as odor, appearance, and texture. Phenomena such as settling, water content, and soil consistency are also explored. These observations are then related to plant growth, as students plant cucumber seeds in a clear plastic tube. By observing root growth, students learn about the role of roots in keeping the plant anchored and upright. In a final activity, students apply what they have learned to investigate a sample of local garden soil.

Solids and Liquids
Catalog no. LF-97-1401
ISBN 0-89278-993-X
Subject: Properties of solids and liquids
Students investigate the similarities and differences in a variety of common solids and liquids. First, they observe, describe, and compare a collection of solid objects, focusing on such properties as color, shape, texture, and hardness. They also perform tests to determine whether the objects roll or stack and float or sink, as well as whether they are attracted to a magnet. Investigations of liquids center on how various liquids look and feel, their fluidity, how they mix with water, and their degree of absorption. In a final lesson, students compare the properties of solids and liquids and identify how they are similar and different.

Sound
Catalog no. LF-97-2201
ISBN 0-89278-966-2
Subject: Characteristics of sound
Using tuning forks, slide whistles, strings, and other sound-producing objects, students investigate the characteristics of sound. They learn that sound is caused by vibrations and explore how sound travels. They learn about the relationship of pitch and volume to the frequency and amplitude of vibrations. They discover, for example, that they can alter pitch by varying the length or tension of a string. Constructing simple stringed instruments, they discover how they can increase the volume of the sound produced by the strings. Students investigate the characteristics of another common sound-producing mechanism—the human vocal cords—and build model vocal cords. They also learn about the anatomy and functioning of the human ear. They apply what they learn in the unit by designing and building musical instruments or other sound-producing devices.

Weather
Catalog no. LF-97-1201
ISBN 0-89278-996-4
Subject: Weather
This unit introduces students to the concept of weather and how it affects their lives. Using a variety of tools, students observe, discuss, measure, and record data on cloud cover, precipitation, wind, and temperature. They learn how to read a thermometer and construct a rain gauge to measure precipitation. They also study cloud formations and use a wind scale to estimate the speed of wind. To apply their new skills and knowledge, students compare their own weather predictions with an actual weather forecast and use the weather data they have collected to form generalizations about the weather in their own locale.